An in vitro assay of leukocyte migration inhibitory activity from human lymphocytes stimulated with concanavalin A.

Human venous blood lymphocytes, incubated for 22 h in serum-free culture medium with the plant mitogen concanavalin A (Con-A), elaborated products, which inhibited the migration of human buffy coat cells under agarose. Con-A was removed by applying the supernatants on small Sephadex G-100 columns. The leukocyte migration inhibitory activity (LMIA) was tested in a semi-quantitative modification of the indirect leukocyte migration agarose technique, which is described. Lymphokine activity, demonstrable as early as 9 h after activation of lymphocytes, was most pronounced after 22 h. Significant LMIA was demonstrated in 12 of 17 normal individuals at standard dilution of culture supernatants I/3. In 9 of the 12 experiments, assays of LMIA were carried out on stepwise diluted supernatants with detection of the greatest dilution with significant LMIA. In four experiments LMIA could only be detected after 3- to 12-fold concentrations of supernatants. Considerable individual variation was found, the amounts of LMIA varying by a factor of about 300. The reproducibility appeared to be quite high, but the factor stability of supernatants stored at -20 degrees C was surprisingly low.